Motor fuel



ELBRIDGE W. STEVENS, OF BALTIMORE, MARYLA 'ND, ASSIGNOR- TO CHEMICAL FUEL COMPANY OF AMERICA, INC, OF LOUISVILLE, KENTUCKY, A CORPORATION OF DELAWARE 4 MOTOR rum...

No Drawing. Application filed March 9,

To all whom it may concern:

Be it known that I, ELBRIDGE WEBSTER STEVENS, a citizen of the United States, residing at Baltimore, in the State of Maryland, have invented certain new and useful Improvements in Motor Fuels, of which the following is a specification.

This invention relates to motor fuels; and it comprises a composite motor fuel consisting of a hydrocarbon oil, such as kerosene (or other petroleum oil) and alcohol (together with a hydrocarbon blending agent if necessary,) and in addition containing a small amount of a readily volatlle ester of formic acid, such as methyl formate or ethyl formate; all as more fully hereinafter set forth and as claimed.

In the manufacture of many composite motor fuels by methods now in use, or proposed, the bulk of the composition is made of alcohol and .a petroleum or coal tar hydrocarbon oil. Kerosene and even heavier oils, such as gas oil or solar oil, 4

are used. Or specially made distillates may be used. Usually a blending agent, such as benzol, is used to promote miscibility of the oil and alcohol and make the compo-- sition stable. For this purpose any cosolvent can be used; that is a body capable of dissolving both the alcohol and the oil, or of dissolving in both.

With most of these compositions it is desirable to use a modicum of some rather volatile combustible body to give quicker ignition in the engine. The petroleum oils ordinarily employed in these mixtures are not very volatile and the alcohol is not as readily volatile as is desirable for engine purposes. As this quick-ignition material various esters of acetic acid, such as ethyl acetate, methyl acetate, butyl acetate, etc, made by combining acetic acid with the corresponding alcohol have been proposed and used, as they are highly voltatile, readily combustible bodies. Valerates, buty rates, etc., have also been proposed. The use of these materials is, however, subject to the objection that in the engine. cylinder they tend to decompose more or less with the re-formation' of the original alcohol and of the acid from which they were made; re-forming acetic acid-in the case of ethyl or methyl acetate. The amount of this acid is not large, but it is suflicient to produce more or less corrosion of metal parts con- Sp ecification of Letters Patent.

Patented May 2,1922. 1920. Serial No. 364,386.

tacting with the explosion gases to obviate the effects of this acidity it has been proposed in the prior art to incorporate a baslc body capable of neutralizing the acidity developed.

In the present invention in lieu of using. these estersI employ the corresponding esters of formic acid which, unlike the acetates, butyrates, yalerates, etc., do not break up with formation of free acidssince acidity does not develop the use of basic bodies is unnecessary. The formate esters are even more volatile than the acetate esters, so that smaller quantity suflice's to give quick ignition to the fuel; and they are also held back better by the composition. Acetic acid esters tend to evaporate away from oil-alcohol compositions in time; this tendency being reater than with the formates. Ethyl or'mate, methyl format:

or butyl formate may be used for the pics i ent purposes.

Formic acid has the empirical composition of CH O and when heated it breaks up readily into H 0 and CO; neither of which is acid. Similarly, ethyl formate and methyl formate on heating ield the corresponding alcohols and CO. 0th are therefore harmless in the engine.

Ethyl formate may be readily made by distilling ethyl alcohol with sodium formate in the presence of an acid, such as hydrochloric acid or sulfuric acid. The sodium formate is readily obtained commercially and. is a cheap material made by absorbing.

the carbon monoxid of producer gas with caustic soda. Methyl for-mate maybe made from sodium formate and methyl alcohol in thepresence of an acid. Ethyl formate boils at 55 C. or 131 F. and has a high vapor tension at ordinary temperatures.

Methyl formate is still more volatile, boiling at about 30 C. or 86 F. While I have described the use of the formate esters more particularly with regard to the composite fuels made up of admixed hydrocarbon oils and alcohols, it is obvious that they may be used with either alone or .in admixture with any motor fuel to which it is desired to givea quicker ignition.

It is not ordinarily necessary of desirable to use more than a very small quantity of formate esters; say not more than about 5 per cent on the weight of the total composition. For some aviation fuel the amount may be somewhat increased; but ordinarily the amount mentioned Will sutfice. A I

A typical composition under the present invention can be made by blending say, 75 parts of a suitable petroleum distillate with about 15 parts of alcohol, using about 5 parts of toluol as a co-solvent or blending agent. To this mixture may be added about 5 partsof ethyl formate or methyl formate. The petroleum distillate used may be ordinary kerosene,-gas oil, cracked distillate,

purposes, as in making etc, or various petroleum distillates may be blended. The composition will tolerate a considerable proportion of rather heavy distillate.

What ll claim is A motor fuel of the same general character as gasoline consisting ota petroleum distillate, alcohol, a hydrocarbon blending agent and a small amount of a readily volatile formic acid ester.

In testimony whereof, I afiix my signature.

ELBRIDGE W. STEVENS 

